Toothbrush



G. S. CLEMENS May 3, `1960 TOOTHBRUSH 4 Sheets-Sheet 1 Filed Feb. 10, 1956 w m. W r w @e @y e.; a/w ne Imdw o e 6d 7@ May 3, 1960 G. s. CLEMENS TOOTHBRUSH 4 Sheets-Sheet 2 Filed Feb. l0, 1956 May 3, 1960 Gjs. CLEMENS 2,934,776

TOOTHBRUSH Filed Feb. 10, 1956 4 Sheets-Sheet 3 May 3, 1960 G. s. cLEMENs TOOTHBRUSH 4 Sheets-Sheet 4 Filed Feb. l0, 1956 2,934,776 roornnnusrr George S. Clemens, Chicago, lll. Application Feist-nary io, 1956, serial m5564316 s claims. (ciales-167) f'My invention autres aan 'finiprvedtastabmost construction whereby desirable Vlongitu'dirial tooth brush- 'ng motionsare facilitated.

For manyV years the dental profession has recognized fthat `,effective `cleaning ofthe A'human teeth is .best 4ac- "c'rriplished by brushumovements*longitudinal of the teeth.

Movements of this 'kind permit the bristles of the vbrush v'to extend'into the comparatively narrow elongated spaces between the teeth where food tends to collect and hence form Afocal points of tooth decay. Moreover, lit is also desirable that ihetooth brushing movements be Efrom themarg'ins ofthe lgums to'the'ends ofthe teeth, rather than inthe opposite direction. This is because toot cleaning movements in the opposite direction repetitively push back the margins of the gums and thereby expose "the 'dentine When the dentine is exposledfit4 readily'delcays. In addition, when the gum margins are 'pushed "back food on the teeth may be pushed underv the ygums and'submarginal decay takes place. This results in total loss of theteeth. Additionally, it is recognizedthat a toothbrush 'should s'erve to vmassage 'and -stiimulate the 'gums themselves. -Such action Vshould be `obtained by "movements in the longitudinal direction `of the teeth since the portion of the gums `betweenthe teeth vis other- `wise difficult or impossible to reach.

While the desirable tooth brush mvements'have long "been known, most persons -in jactualfprctice do not use them. Thisuis because such movemente are cumbersome, tiring, and diihcultwithavailable toothbrushes. Rather,

most lpersons brushtheir teeth with a cro's'swise Abrush r'n'otion that is effective in cleaning the tooth surfaces ex- `th`eilngitudinal recesses betweentheteeth. t

In accordance Ywith the 'present4 invention desirable longitudinal 'brushing l actionv is facilitated by 4providing a toothbrush which lends itselftos'uch'action. `Int-brief, the brushincludes a handle adapted to ybeheld in the hand. In use the handle is rotated about an axis whose "position is determined by the 'natural wrist andV arm articulation. A head isrnounted on'the handle withdbristles oriented'in planes normalto this axis so thatthey execute brushing motions when the handle is so rotated. The

bristles are Amounted and'cut to dene an arcuate-convex envelope forming a fragment of'a cylinder encircling the axis. The envelope of the bristles hasa substantial extent'in the arcuatedirection'so'that asthehandle is rotated there is effective sustained tooth brushing action.

'Handle conformations are Yprovided to orient the handle `a movement that brings the successive bristles A*down on 'and longitudinally "along 'the "teeth, "However, l"the ,Qtr-GC@ .lposed to such lmotion vbut is Vineiectivel in reaching into 2,934,776 iatented May. 3, 1960 `bristles inherentlysweep away from the teeth as they approach the opposite gums, so that the longitudinal brushing action provided does not tend to push the gums back. Ratherthe bristles clear the'lower gums on down stroke Vand the upper gums on up stroke. With respect vto inside 4faces of the Ateeth the brush is Vheld with the "that `the margins of the gums are not pushed back during this operation. Experience has shown that at this time .the slight orbital rnotionis reasonably easy to execute. -15

It is accordingly a general object of the-present invention to provide an improved toothbrush particularly suitable fforbrushing movements longitudinal of the teeth and clearing the gum margin in the direction of the stroke "that would otherwise be pushed back.

Another object vof the present invention is to provide an improved toothbrush wherein the desirable brushing movements longitudinally 'of' the teeth and away from the gum margins are effected `withoutcumbersome, difficult, orvtiring finger hand or arm movements.

`Still another object of the present invention is to provide an improved toothbrush which facilitates brushing movements in the longitudinal direction of the teethand can be eiectivelyapplied to'A all tooth surfaces, including the inner andouter'faces of lboth the centerand side teeth. j

Another object of the present invention iszto provide a toothbrushof the foregoing type having hand-receiving conformations which position the brush as required `for effective tooth cleaning movements.

Additionally it is an object of the present invention to provide an improved toothbrush which accomplishes the foregoing objects with a structure that is simple, easily used',A inexpensive, and readily -manufactured from the materials currently used in the Vmanufacture of toothbrushes., t t y AIt is still another object of the present invention to provide -a toothbrush which in ac tual use with convenient and normal hand and arm articulations in conjunction with the forces associatedwith brushing operation tends to clear the lower gum margins on downstroke and the upper gum margins on upstroke while massaging the upper gum margins on down stroke and the lower gum `margins -on up stroke. j

The novel features Which-l believe to be characteristic of my invention are set forth `withuparticularity inthe appended claims. My invention itself, however, together with furtherobjects and advantages thereof, will best be understood by reference to the following description taken in conjunction with the accompanying drawings in which: l Figure 1 is a" top plan view of one form of a toothbrushconstructed in accordancewith the present invention;

FigureZ -is a-side elevational view of the toothbrush ofHFigure 1; v v

Figure 3 is a View of the toothbrush of Figures 1 and 2 showing how itis held in the hand for one position of tooth brushing movement;

Figures 4, 5 and 6 are cross-sectional views through axes 4 4, 5 5, and o-6, Figure 2, respectively; 'Figure 7 is a cross-sectional view through axis 7-7, Figure 2, with the cylinder defined by the envelope of the brushes shown in dashed line form to illustrate the construction of the brush;

t Figures 8 and 9 are views like Figure 7, but showing alternative forms of the toothbrush of Figures 1 to 7;

native vform of the present invention;

Figure 11 is a side elevational view of the toothbrush fof Figure Figure 12 is a view showing the brush of Figures 10 :and 1l as held by the hand for use; v

Figures 13, 14 and 15 are cross-sectional views through :axes 13a-13, 14-14, and 15-15, Figure 11;

Figure 16 is a fragmentary cross-sectional View of the front portion of the human mouth with the form of the toothbrush of Figures 10 to 15 in the position assumed at the beginning of the down stroke;

Figure 17 is a view like Figure 16 but showing a later point in the down stroke of the brush;

Figure 18 is a view like Figures 16 and 17 but showing the brush at the beginning of the up stroke;

Figure 19 is a view like Figures 16 to 18 and showing the brush in a later position of the up stroke;

Figure 2() is a fragmentary cross-sectional view of the human mouth in the partially open position and showing in cross-sectional view the toothbrush of Figures 1 to 7 as used to brush the inside top faces of the teeth;

Figure 2l is a cross-sectional View through axis 21-21, Figure A20; Y

Figure 22 is a View like Figure 20 showing the use of the brush to clean the inside faces of the lower teeth; and

Figure 23 is a view generally like Figure 15 but showing an alternative way to obtain an envelope of arcuate conformation as defined by the bristles.

Referring to Figures l to 7, the form of the brush there shown consists of a handle indicated at H, a shank indicated generally at S and a head or brushing portion indicated generally at E. Preferably these are of unitary one-piece plastic construction with the bristles B embedded in and anchored to the head E as is further described hereafter.

The handle H Vis of elongated conformation to be gripped by the human hand as shown in Figure 3 and as further described hereafter. The handle H is generally divided into a forward portion indicated at 30 and an aft portion indicated at 32. As seen best in Figure 6, the aft portion 32 is of paddle-like conformation.

it tapers to this shape from the rectangular conformation of forward portion 30 by the gradual tapering shown in the figures. This paddle conformation not only de fnes an aft portion 32 of lightweight and attractive appearance, but it also serves to orient the head portion E when the fingers are wrapped around the handle. This is shown in Figure 3 and further described hereafter. Preferably the aft portion 32 tapers in a diamondlike conformation as shown in Figure 6, rather than in a general oval shape. This tends to keep the aft portion of the handle from slipping. About the rear onethird of the handle has the diamond conformation, about the center one-third is preferably oval, and about the forward one-third is enlarged as shown and above described.

The forward portion 30 of the handle H is of generally rectangular conformation as is seen in Figures 4 to 6. A series of four finger-receiving depressions or cups are formed in its surface. One such cup, indicated at 34, Figures l, 5 and 6, is formed in the top face of the handle adjacent the junction with the shank S. This cup serves to receive the-index linger or thumb to support the brush in some conditions of useas is hereinafter described. This cup has fa comparatively shallow forward part 34a and a comparatively deep rear part 34h. Cups 36 and, 42 are formed opposite the cup 34 as shown in Figures 3, 5 and 6 and are of somewhat shallower conformation. Cup 36 receives the index finger under some conditions of brush use. The side finger receiving cups 38 and 40, Figures 2, 5 and 6, are formed in general alignment with the cups 34 and 36 and on the opposite sides of the forward portion of the handle. These receive the thumb and index finger as shown in Figure 3. v

A finger receiving cup 42V is on the forward face of the forward portion 30 of handle H, as shown in Figures 3 and 4. This cup is adjacent the cup 36 but faces in a different direction and is somewhat deeper. It serves as a convenient surface against which the thumb can be placed to prevent longitudinal slippage of the handle H in the hand.

The shank S is of elongated conformation as shown in Figures 1 to 4, inclusive. It is about 1/3 of the length of the handle H and is formed unitarily therewith. The shank S extends olf of the front or forward portion 30 of the handle H at a position generally registered with the top surface of the portion 30 of the handle H and is shown in Figure 2.

The head E consists of a base portion 44 which, as seen in Figures l, 2, 3 and 7, is of arcuate conformation. This portion of the head E is centrally disposed upon and carried by the shank S as shown. The base portion 44of the head E has a substantial length longitudinally of the brush for the reasons hereinafter described and in addition has a substantial length or extent in the arcuate direction as seen in Figure 7.

The base 44 of the headV E receives a plurality of bristles B which are anchored therein in any one of the methods well known to the art. Preferably, these bristles are formed in tufts 46, Figure 2, which are individually embedded in and anchoredto the base 44. For best operation of brushes constructed in accordance with the present invention it is desirable that as large a number of tufts and bristles as possible in relation to the size of the base 44 be used. This is especially desirable to prevent mushing of the bristles during brushing action.

The ends of the bristles 46 are cut to form an arcuate envelope. This is shown in detail in Figure 7. This envelope forms a portion or a fragmentary segment of a cylinder as indicated by the dashed lines 48, Figure 7. This cylinder has an axis indicated at 48a, Figure 7, which is located substantially above the parts of the brush as shown. As is hereinafter described in detail, the brush in use is rotated about axis 49 which is located between the ends of the bristles B and the center 48a.

In the form of the brush of Figures 1 to 7, the head E is centered along the vertical axis of the handle vH. It has also been found desirable to center the head E along an axis 50-50, Figure 8, which is angularly disposed in relation to the up and down axis of the head H. In this construction as shown in Figure 8 the angle or tilt of axis 50-50 is about 20 and axis 50-50 passes through axis '48a of the cylinder defined by the bristles. A similar effect can be secured by the construction of Figure 9 where the head is centered on an axis 52-52 which passes through the centerdelined by the rectangular part of the handle as shown and is similarly rotated 20 in relation to the up and down axis of the handle H.

Figures 10 to 15 show an alternative embodiment of the present invention. In the brush of these figures there is likewise a handle H, a shank S, and a head E. The head E likewise receives bristles B which as shown in Figure 15 have their ends cut to arcuate conformation. The head E is similarly of substantial extent lengthwise of the brush and substantial extent inthe arcuate direction as shown.

The handle H, of the form of the brush shown in Figures 10 .to l5, has an enlarged aft portion 132 of generally circular outline as shown in Figures 13 and 14. The forward portion of this handle tapers down from the aft portion 132 and has a series of four finger receiving flats, one in each of four positions. These are indicated at 13 4, 136, 13S and 140, Figures l0, 1l, l2 and 14. These ats form faces against which the fingers bear to hold the brush in vdesired position of rotation. The engagement of the palm of the hand with the enlarged aft portion 132 of the brush additionally serves to anchor it in position. It will be further noted that the front face A142 of the handle serves as a face against which the index assert-e tnger or thumb may be placed to hold the brushV against longitudinal movement in the hand.V The shank S is adjustably positioned in relation to the handle H in the form of the invention shown in Figures to 15. This is accomplished by a movable carriage 100 which is of rectangular cross-section as shown in Figures 1,0 and 12 and is movable up and down in a complementary mating rectangular slot formed in the forward end portion 130 0f the handle H. The shank S is anchored in the movable part 100 by the set screw 102 as shown in Figure 13. This method of anchoring also permits adjustment of the rotation position of the shank S in relation to the handle H. The movable carriage or base 100 is anchored in desired position of eccen- .tricity on the handle H by the set screw 104, Figure 13.

For use, the shank S is positioned inrelation to the handle H as is shown in Figure 15 With this positioning of the head E, the bristles 146 define an envelope 148 of arcuate conformation forming a cylinder having an axis 14811 as its center. In the use of the brush in Figures 10 t'o 15, normal hand articulations and arm articulations rotate the brush about the axis 132a, which is the axis of the portion 132 of the handle H. This is because in the form of Figures l0 to l5 the brush is held in the palm of the hand like a screw driver. It will be observed that the length of the radius struck between the ends of the bristles 146 and the axis 14811 is greater than the distance between the ends of the bristles and the axis 13241 about which the b rush is rotated.

Figures 16 to 19 show the action of the brush of the present invention in cleaning front faces of the teeth. For purposes of illustration, the brush shown is that of Figures 10 to l5, although it will be understood that other forms of the brush might as well be shown. With refer ence to Figure 16, it will be noted that the teeth extend in mating rows from the upper jaw 200 and the lower jaw 202, the upper teeth being indicated at 204 and the lower teeth at 206. The iiesh of the gums, indicated at 208 in the case of the upper teeth and 210 in the case of the lower teeth, cornes down over the teeth to form the marginal areas 20861 and 210a, respective-ly. It is these marginal areas that are of primary importance in connection with the cleaning of the teeth. If the brush tends to push the gums in these marginal portions back away from the teeth, the teeth are uncovered and the dentine which is located immediately below these areas is thereupon exposed. The exposed dentine readily decays. Also, as above described, there are other reasons why it isV very important that the flesh of the gums not be pushed back in these marginal areas. At the same time, however, it is equally important that the marginal por tions 208e and 21051 of the gums be massaged and that the bristles '146 sweep over and clean the adjacent surfaces ofthe teeth. t

" In Figure 16 the brush is shown at the beginning of a down stroke. At this time the handle is held to rotate the bristles 146 from position in facing relation to the teeth and with the lower bristles against the upper teeth 204, as shown. Also it will be noted that the head E of the brush is poised for do-wnward rotations in the clockwise direction as seen in Figure 16.

For tooth brushing action the handle is now rotated by wrist and arm articulations to sweep the bristles 146 clockwise in the down direction as shown by the arrow A, Figure y16. As this stroke proceeds it will be observed that the bristles 146 contact theupper gums 208 in the marginal portions 203e and likewise contact and sweep across the faces of the upper teeth 204. As this action takes place, the bristles 146 tend to sweep away from the lower teeth 20,6. This is because the rotations of the brush as shown in Figure 16 are about axis 13`2a, Figures 16 and 15. As above described in connection with Figure 15, this axis denes a shorter radial distance to the envelope of the bristlesthan does the axis 148:1 of the cylinder which is defined by the bristles. Also the` axis 132:1 during the downstroke is located' slightlyaboye the line of contact between the teeth, as shown.- In. consequence of this action, the forward or leading bristles tend t0 follow the line of travel indicated by dashed line 104, Figure 16. It also permits the bristles to sweep away from the lower teeth 206 and the lower gums so that the marginal areas 210a are not contacted during this brush motion.

, Figure 17 shows the position of the brush towards the end of the down stroke shown in its inception in Figure 16. At this time it will be observed that the bristles 146 entirely clear the lower teeth 206 as well as the gum margin 210a. stroke to push back this gum margin and thereby expose the dentine of teeth 206.

Upon completion of the down stroke of Figure 17 the brush is now rocked or rotated upwardly by natural hand and arm articulation. At this time natural movement causes the head E to move somewhat downwardly and inwardly and thereby position the axis of rotation 132g: below the line of contact of the teeth, as shown in Figure 18. Thus in its inception, the up stroke commences with brushing action in the lower gum 210 and especially the marginal portion 210e. The up stroke continues in natural hand and arm articulations to tend to sweep the forward bristles 146 along the dashed line 106, Figure 18. It will` be noted that this dashed line brings the bristles against the lower teeth 206 and the marginal portions 210a of the gums but clears the upper parts of the upper teeth 204 and the upper marginal portions 208e of the gums.

Upon completion of the up stroke the brush has the position of Figure 19 where it is clearing the upper regions of the upper teeth 208and the upper marginal portions 208a of the gums as above described.

With the form of the invention of Figures l to 7, action similar to that above described takes place.

In executing the above described movement with the brush of Figures 10 to 15, the user preferably uses two ways of holding the brush. On the front and left sides of the mouth the brush is held with the thumb on face l and the foreiinger against the indexing faces 1,34 and 138. On the right hand side of the mouth the thumb and forenger positions are reversed so that the thumb rests on face 138 and the index linger on faces 136 and 140. With the brush thus positioned and held in the hand the above-described natural hand and arm articulations will provide the desired brush rotations.

' Similarly, with the brush of Figures 1 through 7, de-V sired rotation may be achieved by putting the thumb in the cup-shaped portion 40 and the index finger in the opposite cup-shaped portion 38, as is shown in Figure 3,

foi` the left and center of the mouth. For the right side p of the mouth it lis convenient to place the thumb in cup 38, the second ingerin cup 40'. and the forenger in the deep cup 34 or along the shallow groove portion 34a of cup 34.

With either type of brush, the user may prefer to shift the brush to other positions.

Figures 20, 21 and 22 show how the brush of the present invention is used to clean the inside surfaces of the teeth. In cleaning the upper teeth the brush handle H is simply gripped in the fist and the head E and bristles 146 positioned in the up position as shown in Figure 20. Preferably the thumb rests on flat 142, Figure 10. It will be noted from Figure 21 that at this time the bristles fit within the arcuate conformation of the teeth so that they serve to engage and clean a considerable number of the teeth at one time. referably the user executes a slight orbital movement of the brush during the cleaning operation shown in Figures 20 and 21. This movement is suchk as to tend to bring the ends of the bristles 146 in an elongated, elliptical path 108, Figure 20. It has been found comparatively easy to provide brush movementl approximating this action. It may also be achieved in part by, rocking movement of the brush. In any event it Thus there is no tendency for this down spedire serves to avoid brush action which tends to push back the marginal portion 208b of the gums.

With the brush of Figures 1 to 7, the movements of Figures 20 and 21 are most conveniently executed with the thumb in cup 34 and the forefinger in cup 42 or 36.

The mode of cleaning the inside faces of the lower teeth 206 is shown in Figure 22. The action in this instance is like that of Figure 20 excepting that the lower teeth are involved and the'handle H of the brush accordingly extends upwardly from the teeth. This movement is best made by holding the thumb on fiat 136 and the forefinger on flat 134. With the brush of Figures l to 7 this motion is best done with the thumb in cup 42 and the forefinger in cup 34.

It will be noted in connection with the action of Figures 20 to 22 that when the brush of Figures 1 to 7 is used there is a smooth continuous surface on the back side of the brush. This has the advantage of not tending to damage the lips or teeth which bear against this surface, particularly when the rear teeth are being brushed.

Itwill further be noted that in the brushing action of Figures 20 to 22 the brush is moved longitudinally up and down and for effective action it is necessary that the brush not slide in the hand of the user. The linger receiving portions 34 and 42, Figure 1, serve as a convenient surface against which the index finger or the thumb may be positioned to prevent such sliding action. The surface 142, Figure 11, provides a similar type of face to be engaged by the thumb or forefinger if desired. v

It will be observed that, from the above description, the bristles 46, Figure 1, and 146, Figure l0, form an arcuate envelope defining a fragment of a cylinder. In the forms of the invention above described this is accomplished by having an arcuately formed base 44 (144, Figure 10) in which bristles of like length are embedded. In the alternative construction of Figure 23 the head 244 has a flat back face 244e and an arcuate front face 244b. In this instance the bristles 246 are similarly cut to like lengths.

For the operation of the toothbrush it is unnecessary that the bristles becut to form a portion of a circular cylinder. Rather, the cylinder defined in part by the arcuate envelope of the bristles may deviate from a circular shape without substantially altering the operation of the brush. The important thing is that, in use, the bristles rotate about a center closer to the envelope they define than the distance between the envelope and the center of curvature of the bristles. In other words the rotation in use must be such as to cause the bristles to clear the lower gum margin or down stroke and the upper gum margin on up stroke.

The action above described in relation to Figures` 16- 18 is an idealized representation of what occurs during actual tooth brushing operations. In practice the brush, as used, departs from this action to a degree dependent upon the personal preferences and tendencies of the user, which departures do not detract from the basic character of operation of. the brush. Applicant has tested brushes with adjustable shank positions, such as the brush of Figures 10-15, with various shank positions. In practical use with various subjects it has been found the criterion of effective operation is that the en` velope of the bristles have a greater radius of curvature than the distance between the envelope and the axis about which the brush rotates in use.

In use the brush of Figures 1 to 7 is held by the fingers as shown in Figure 3 so that the axis of the handle is considerably spaced in relation to the wrist. The brush of Figures 10 to 15 is held by the palm of the hand with the lingers wrapped about the handle as if holding a screw driver, as shown in Figure 12. In this case the axis of the handle in substance passes through the wrist` and rotating motions of the wrist in normal articulations make the brush rotate about the axis of the handle. vSince, with the brush of'Figures l to 7 the normal movements rotate the brush about an axis considerably spaced from the axis of the handle,v it is necessary to locate shank S, Figure 7, and the base 44 of the head E-near the top surface of the brush. The envelope of the bristles B then defines a cylinder having its axis-48a located a greater distance from the envelope of the bristles than the distance between the envelope and the axis 49, Figure 7 about which the brush is rotated. .In the brush of Figures 10 to 15 the shank S andthe base 144 of the head E are located near the bottom part of the handle H. The envelope of the bristles B then defines a cylinder having its axis 148a located a greater distance from the envelope of the bristles than the distance between the envelope and the axis 103 about which the brush rotates.

kThe construction of Figures 1-7 has an advantage in the fact that the top face running from the center part 0f the upper surface of the base 44 of the head E, along the shank S, and along the forward part 30 of the handle H, is-a smooth continuous surface without discontinuities. When the inner faces of the teeth are brushed, as in Figures 20-22--and particularly when the rear teeth are involved-the fiesh of the mouth bears against this surface. Since this surface is smooth, the brush can be moved back and forth without injuring this flesh.

With the brush of the present invention it is desirable to arrange the bristles B to form an envelope of substantial extent in both the arcuate direction and in the direction of the length of the brush. With respect to the arcuate direction, the extent is required to give effective brushing operation over a considerable angle of brush rotation, as is shown in Figures 16 to 19. With respect to the extent along the length of the brush it is desirable to have sufficient extent to brush a substantial number of teeth simultaneously so that the brushing operation is promptly completed.

`The curvature of Vthe envelope defined by the bristles is also chosento fit well into the inside of the teeth, as is shown in Figure 21. Since the bristles bend and thereby accommodate themselves to the varying curvatures inside the teeth, the curvature required by this consideration is not critical.

The constructions of Figures 8 and 9-where the axis of symmetry of the head is tilted in relation to the handle-have the advantage of being somewhat easier to manipulate than the form of Figures 1 to 7.

It will be seen that the surfaces 38 and 40, Figure 5, and 138 and 140, Figures 13 and 14, form indexing conformations adapted to receive the thumb and a finger of the user. These serve to orient the brush in position for brushing movement and resist rotation of the brush in the fingers and additionally serve to position the fingers so that when the handle is moved under normal arm and wrist articulation the brush rotates about a predetermined axis as described above, kIt will be noted that these finger receiving conformations form a set in each instance. The thumb and a finger are received by these conformations to brush the outer faces of the teeth on one side of the mouth as is explained above, while the positions of the thumb and finger are reversed to brush the outer faces of the teeth on the other side of the mouth. The brush has another set of finger receiving conformations (34 and 42, Figures 4 and 5; 136 and and `142, Figures 10, 11 and 14) which receives the thumb and a finger when brushing the inside faces of the teethand holds the brush against longitudinal slip in relation to the hand.

The term opposed gum margin or opposing gum margin is here used to designate the gum margin located in the direction of movement of the brush, i.e., the gum margin that would be pushed back to expose the dentine if substantially engaged by the moving brush.

While I have shown and described specific embodiments of the present invention it will, of course, be understood that other modifications and alternative constructions may be used without departing from the true spirit and scope of the invention. I therefore intend by the appended claims to cover all such modifications and alternative constructions as fall within their true spirit and scope.

What I claim as new and desire to secure by Letters Patents of the United States is:

1. A brush for cleaning the outer faces of human teeth in sweeps longitudinally thereof and away from the margins of the gums, the brush comprising: a head having a base; bristles protruding from the base in planes normal to -a predetermined axis and cut to define a con vex envelope forming a fragment of a cylinder about said axis and symmetrical about a predetermined plane extending through said axis, the radius of said cylinder being at least twice the protruding length of the bristles from the base; a lengthy handle affixed to said head with its lengthy direction parallel to said axis, said -handle having a shank portion aflixed to the base of the head, located in said predetermined plane, and extending parallel to said axis, the handle further having a forward portion afiixed to the shank portion and offset in said predetermined plane in the direction the bristles protrude -from the base, said forward portion being of generally rectangular cross-section in planes normal to said axis and having a pair of opposed faces spaced to receive the thumb and Iforefnger of the user, on opposite sides of said predetermined plane, ,and bounded by edge portions extending generally parallel to the axis, whereby with the thumb and forefinger seated on said faces the bristles face the user and the edge portions resist rolling motion between the thumb and forefinger of the user, the handle further having an aft portion of gradually decreasing cross-section and extending away from the forward portion to be received in the fingers and hand of the user, whereby normal wrist and arm articulation causes the bristles to clear the gum margins of the upper teeth on the up stroke and the gum margins of the lower teeth on the down stroke.

2. A brush for cleaning the outer faces of human teeth in sweeps longitudinally thereof and away from the margins of the gums, the brush comprising: a head having a base; bristles protruding from the base in planes normal to a predetermined axis and cut to define a convex envelope forming a fragment of a cylinder about said axis and symmetrical -about a predetermined plane extending through said axis, the radius of said cylinder being at least twice the protruding length of the bristles from the base; a lengthy handle aixed to said head with its lengthy direction parallel to said axis, said handle having a shank portion aflixed to the base of the head, located in said predetermined plane, and extending parallel to said axis, the handle further having a forward portion aixed to the shank portion and offset in said predetermined plane in the direction the bristles protrude from the base, said forward portion being of generally rectangular cross-section in planes normal to said axis and having a pair of opposed faces spaced to receive the thumb and forenger of the user, on opposite sides f said predetermined plane, and bounded'by edge portions extending generally parallel to the axis, whereby with the thumb and forenger seated on said faces the bristles face the user and the edge portions resist rolling motion between the thumb and forefinger of the user, said forward portion further having a second pair of opposed faces generally aligned with and at right angles to said first pair to receive the thumb and forefinger to orient the brush for cleaning inside tooth faces, the handle further having an aft portion of gradually decreasing cross-section and extending away from the forward portion to be received in the fingers yand hand of the user, whereby normal wrist and arm articulation causes the bristles to clear the gum margins of the upper teeth on the up stroke and the gum margins of the lower teeth on t-he down stroke.

3. A brush for cleaning the outer faces of human teeth in sweeps longitudinally thereof and away from the margins of the gums, the brush comprising: a head having a base; bristles protruding from the ybase in planes normal to a predetermined axis land cut to define a convex envelope forming a fragment of a cylinder about said axis and symmetrical about a predetermined plane extending through said axis, the radius of said cylinder being at least twice the protruding length of the bristles from the base; a lengthy handle affixed to said head with its lengthy direction parallel to said axis, said handle having a shank portion affixed to the base of the head, located in said predetermined plane, and extending parallel to said axis, the handle further having a forward portion affixed to t-he shank portion and offset -in said predetermined plane in the direction the bristles protrude' from the base, said forward portion being of generally rectangular crosssection in planes normal to said axis with its sides tilted about 20 in relation to said predetermined plane and having a pair of opposed faces'spaced to receive the thumb and forefinger of the user, on opposite sides of said predetermined plane, and bounded by edge portions extending generally parallel to the axis, whereby with the thumb and -forefnger seated on said faces the bristles face the user and the edge portions resist rolling motion between the thumb and forefinger of the user, the handle further having an aft portion of gradually decreasing cross-section and extending away from the forward portion to be received in the fingers and hand of the user, whereby normal wrist and arm articulation causes the bristles to clear the gum margins of the upper teeth on the up stroke and the gum margins of the lower teeth on the down stroke.

References Cited in the le of this patent UNITED STATES PATENTS D. 165,248 Sherrod et al Nov. 20, 1951 D. 179,441 Clemens Dec. 25, 1956 1,134,459 Kalina Apr. 6, 1915 1,227,412 Fendrich May 22, 1917 1,520,730 Street Dec. 30, 1924 2,304,319 Saltzman Dec. 8, 1942 I FOREIGN PATENTS 76,598 Denmark Nov. 2, 1953 291,657 Great Britain June 7, 1928 

